This invention generally relates to crop harvesters and, more particularly, to an improved, flexible belt conveyor which may be used for moving cut grain from one level in the combine harvester to a higher level. This invention is particularly useful in a drag conveying apparatus in which the material to be conveyed is trapped between a floor and a multiple conveyor belt assembly to effect the upward transport of the material by dragging it up the incline. This is in contrast to the more common method of conveying where the transported material is carried on the upper portion of the belt. It also is useful in hay balers for the formation, containment and compaction of cut hay into large cylindrical bales.
Drag conveyors as known in the prior art are composed of mechanical chains with metal crossbars traversing the open distance between the chains. These chains are composed of a multiplicity of parts, including plates, pins, brackets and miscellaneous linkage parts. These mechanical chain conveyors suffer from a number of problems due to the many parts involved. These mechanical chains are subject to stretching due to wearing and elongation of the holes through which the link pins or other fastening means are located. Over a relatively short period of operation, the mechanical chain will actually expand in overall length by several inches requiring constant adjusting during harvesting operations to take up the slack created. If one of the metal pieces is broken and becomes entrained with the crop that is being harvested, the dislodged part may seriously damage or cause a lockup of downstream processing mechanisms in the harvester including knife cylinders, high speed fans, etc. A major performance limitation of the mechanical chain configuration of the prior art is that it is limited to low speed operation and is objectionably noisy. In addition, continuous maintenance is required on the prior art chains, the need for lubrication is constant, and metal parts must periodically be replaced. The metallic chains are also very heavy and add to the weight of the harvester.
Flexible belts having lugs on one surface adapted for positive driving by a sprocket and having molded transverse ribs on the upper surface are known for crop gathering use. A pair of belts are positioned to entrap grain stalks between the opposed ribbed surfaces of the belts. Such belts suffer the disadvantage that when a transverse cleat is damaged, or ripped off during harvesting operations, the entire belt must be replaced. Such an occurrence is not unusual when crop residue, rocks or debris become jammed in the conveyor. A belt having the transverse molded ribs covering the complete width of the conveying mechanism in a combine adds considerable weight to the harvester and is very expensive to produce as an endless belt without mechanical splice.
U.S. Pat. No. 4,553,663 issued on Nov. 19, 1985 by the inventor herein describes a crop conveying apparatus that uses flexible rubber belts that have transverse connecting links positioned in cleat bores.